Knative simplest event source

DoTheThing.java

import com.fasterxml.jackson.databind.ObjectMapper;
import io.streamzi.cloudevents.CloudEvent;

import java.net.HttpURLConnection;
import java.net.URL;
import javax.enterprise.event.Event;

class DoTheThing implements Runnable {
  // Set up class, etc
  // ...
  @Inject
  @ExternalNotify
  private Event<CloudEvent<MyCustomEvent>> cloudEvent;
  private static final ObjectMapper MAPPER = new ObjectMapper();

  @Override
  void run() {
    // Do all the existing stuff
    // ...
    // ... AND THEN (from https://github.com/project-streamzi/jcloudevents/blob/master/introduction.md):
    CloudEvent<MyCustomEvent> event = new CloudEventBuilder<MyCustomEvent>()
        .eventType("com.just-get-it-done.dept.DoTheThing")
        .source(new URI("/DoTheThing"))
        .eventID(operationID.toString())
        .build();
    cloudEvent.fire(event);
    // Do the rest
  }
  
  public void sendEvent(@Observes @ExternalNotify CloudEvent event) /* throws ... */ {
    String endpointUrl = System.getProperty("EVENT_ENDPOINT");  // The string from status.domain
    String eventToken = System.getProperty("EVENT_TOKEN");  // The string from status.token
    if (endpointUrl == null || eventToken == null) {
      LOGGER.log("No endpoint configured, dropping event");
      return;
    }
    URL url = new URL(endpointUrl);
    HttpUrlConnection conn = (HttpUrlConnection) url.openConnection();
    conn.setRequestMethod("POST")
        // From https://github.com/cloudevents/spec/blob/master/http-transport-binding.md#321-http-content-type
    conn.setRequestProperty("Content-Type", "application/cloudevents+json; charset=UTF-8")
    conn.setRequestProperty("Authorization", "Bearer " + eventToken)
    conn.setDoOutput(true);
    conn.connect();
    MAPPER.writeValue(conn.getOutputStream(), event);
    if (conn.getResponseCode() >= HttpUrlConnection.HTTP_MULT_CHOICE) {
      LOGGER.log("Got unexpected >200 response for message: " + MAPPER.writeValueAsString(event));
    }
  }
  //...
}

simple_source.yaml

apiVersion: eventing.knative.dev/v1alpha1
kind: EventType
metadata:
  name: my-custom-event
spec:
  schema: "object"
---
apiVersion: eventing.knative.dev/v1alpha1
kind: Source
metadata:
  name: do-the-thing
  annotations:
    eventing.knative.dev/cluster-provisioner: simple-ingress
spec:
  provisioner:
    name:
      apiVersion: eventing.knative.dev/v1alpha1
      kind: ClusterProvisioner
      name: simple-ingress
  arguments:
  - name: external
    value: True
  - name: auth
    value: token
# Filled in by server:
# status:
#   conditions:
#   - type: Ready
#     value: True
#   domain: do-the-thing-ab112c.my-namespace.eventing.just-get-it-done.com
#   token: aa87UTe9bZ42Aorb

it would help to also see the simple-ingress provisioner definition

@n3wscott

I think you meant the simple-ingress controller implementation? The provisioner would look like:

apiVersion: eventing.knative.dev/v1alpha1
kind: ClusterProvisioner
metadata:
  name: simple-ingress
spec:
  type: 
    group: eventing.knative.dev
    kind: Source
status:
  conditions:
    type: Ready
    status: True